How the hash generator works
As you type, the text is encoded as UTF-8 and hashed with your browser's Web Crypto API, the same audited implementation browsers use for HTTPS. The hashes are shown in lowercase hexadecimal. Nothing is uploaded.
What hashes are used for
A hash is a fixed-length fingerprint of data. The same input always gives the same hash, and a one-character change gives a completely different one. That makes hashes useful for verifying downloads, detecting changed files, deduplicating data and signing software.